When To Get Your Flu Shot In 2020 — Timing Matters

Here's a sentence you'll be hearing a lot over the next several months: Get your flu shot. Experts, including top docs such as Anthony Fauci, MD, can’t emphasize it enough. Influenza immunizations can help us avoid a “twindemic”. They're critical. But many people are wondering when is the best time to get a flu shot. If you get it too early, will the effects "wear off" before the end of flu season?

We have answers. But first, a quick explainer about why flu shots are so critical: "Getting the shot prevents influenza infection, which reduces the burden on our healthcare system and keeps your immune system protected from the flu,” explains Nate Favini, MD, the medical lead of Forward, a preventive primary care practice. “It also contributes to what’s called ‘herd immunity,’ which reduces transmission of the flu through the population and protects children, older adults and people with medical conditions from the flu.”

In short: It reduces your chances of getting sick. It protects vulnerable populations from getting sick. And it reduces the likelihood that hospitals and health centres will become overburdened again, as flu season and the pandemic converge. Sounds like a win-win-win situation, right?

Right. So, now that you've committed to getting your flu shot, here's everything you need to know about when to do it.

Late October, explains Dr. Favini. Here's why: There’s some evidence that getting a flu shot too soon in the season — such as August or September — might leave you with waning immunity by January or February, he says. That can be a problem, because flu season typically lasts through March, according to the Centers for Disease Control and Prevention. “This might be especially true for people over 65 who don’t tend to have as strong of an immune response to vaccines,” Dr. Favini says.

“On the other hand," he continues, "getting a shot early is dramatically better than not getting a shot at all. So while I tend to think that late October is the optimal time to get a flu shot, if you have a chance to do it sooner and might miss it later in the season, just go for it now.” After getting poked, it’ll take you about two weeks to build up immunity. 

Manufacturers are rolling out the flu vaccine already, and doctors anticipate the full supply being in circulation by the third week of September, explains Charles Golden, MD, vice president and executive medical director, CHOC Children’s Primary Care Network. “Some places have the flu shot already, while others are still waiting on orders [from private manufacturers],” Dr. Favini adds. 

That question is more complicated than you might think. It’s possible that tens of thousands of cases and hundreds of deaths related to the flu could be avoided if older adults waited until October to face the needle, according to a 2019 analysis in the American Journal of Preventive Medicine. Dr. Favini echoes this, and says the optimal time to go in is in October to ensure that the flu vaccine lasts through the winter.

But in 2020, the shot may not be as accessible. There should be enough vaccines to go around — manufacturers produced 20 million more doses in 2020 than they did in 2019, because they’re anticipating higher demand due to the pandemic — but many folks got their shots for free at school or at work last year. This year, so many people are working from home or unemployed, taking away that option. Instead, they'll have to go out of their way to get it at pharmacies and doctor’s offices, potentially increasing their contact with others. Because of these barriers, some health experts are just encouraging people to just get the shot ASAP. 

Flu season typically ends in March, so there’s limited utility in getting shot in the spring. But, in this case, late is better than never. As long as strains of the flu (there are multiple, and the big ones are Influenza A and B) are still circulating, you can get a shot. “It’s only too late when the seasonal supply of flu vaccine is exhausted,” Dr. Golden says. “We typically recommend the flu vaccine for anyone who hasn’t had one in that season, even as late as April or May. Some protection is better than none.” 

Still, the most protection from the flu shot will be gained if people get vaccinated before the virus peaks in local circulation,  which is expected to occur in December and January of this year, Dr. Golden explains. 

The body may have a stronger immune response when the vaccine is given in the morning, according to a study published in the journal, Vaccine. “That might translate to better immunity against the flu,” Dr. Favini says. So sure, consider getting a shot before work — but honestly, there's not enough evidence to prove this is true, or that the effect is particularly profound. So, if after work is more convenient for you, that's fine. The important thing is to just get the shot. “The best time is whatever time is convenient and available for you and your provider,” Dr. Golden emphasizes. 

Despite arguments to the contrary, science says you cannot get an influenza infection from the flu shot, Dr. Golden assures. “There has been extensive research supporting the safety of flu vaccines, and hundreds of millions of Americans have received the vaccine,” Dr. Favini adds. But side effects can include soreness, redness, swelling, headache, fever, nausea, and muscle aches. These side effects are typically mild and will go away in a couple days, he says. 

We'd be happy to say it a million times: Get your flu shot between now and late October. If you miss that window, get it anyway. And after you get it, keep doing all the things you've been doing to stay safe from COVID-19: social distancing, wearing a mask, washing your hands. “The more people that get vaccinated, the more we help protect more vulnerable people like babies who can’t get the flu shot and seniors who are more likely to become very ill with the flu,” Dr. Favini says. “Your shot can save the life of someone you know.”